Victoria Principal fears the proposed expansion of offshore drilling in the Gulf of Mexico and Arctic Ocean could lead to another disastrous oil spill like the one that devastated the U.S. Gulf coast last year.

The "Dallas" actress is making an "extremely generous six-figure donations" to two organizations that lobby against increased offshore oil exploration and for tougher rules for oil companies, those groups said Tuesday.

"Waiting until a disaster happens is waiting until it's too late," Principal said in Tuesday's announcement.

It is second time Principal has made major donations to both Oceana and the Natural Resource Defense Council. The first was in the summer of 2010 when her money helped put an underwater robot off Florida's Gulf Coast to detect any encroaching oil from the BP oil disaster.

"The strategy and campaign must begin now, in order to achieve success and prevent further devastation from increased offshore drilling and by imposing tougher standards and having improved safeguards firmly in place," Principal said. "I hope others will join me at this crucial juncture in the future of our oceans and our planet."

Oceana and the NRDC said they would use Principal's newest donation in the campaign to prevent drilling off the U.S. Atlantic and Pacific Coasts, as well as the campaign to "require critical scientific assessments and demonstrated oil spill response capability in the Arctic before allowing additional leasing."

"Americans watched in horror and disbelief as millions of gallons of oil spewed into the Gulf of Mexico during the BP disaster nearly two years ago," NRDC President Frances Beinecke said. "If we've learned anything from this tragedy, it's that we must not allow it to happen again."

Principal's second donation is key to continuing the fight to protect American coastlines "in the wake of the disastrous Gulf oil spill, and now on the heels of the Obama Administration's 5-year drilling plan," Oceana CEO Andrew Sharpless said.

Principal was a celebrity volunteer in June 2010 when a CNN telethon, hosted by Larry King and Ryan Seacrest, raised more than $1.81 million for Gulf Coast oil disaster relief.